pH值对活性污泥胞外聚合物分子结构和表面特征影响研究

pH1,2,1,1(1,150090;2,100875):(extracellularpolymericsubstances,EPS),pH,2,pHEPS,,EPS,.,(pH3),EPS50%,30%,65%~70%;(pH11),EPSpH720%~30%,15%,20%~50%.,,(pH3);,2EPSpH;,,.pHEPS,EPS,.:;;pH;;:X7031:A:02503301(2007)07150705:20060713;:20061110:(2005038197);(2003AFXXJ025):(1980~),,,,Email:[e-mail]ceCharacteristicsandMolecularStructureofExtracellularPolymericSubstancesfromActivatedSludgeZHENGLei1,2,TIANYu1,SUNDezhi1(1SchoolofMunicipalandEnvironmentalEngineering,HarbinInstituteofTechnology,Harbin150090,China;2CollegeofWaterSciencesKeyLaboratoryofWaterandSedimentSciencesMinistryofEducation,BeijingNormalUniversity,Beijing100875,China)Abstract:Tounderstandthemechanismsofextracellularpolymericsubstances(EPS)influencingsludgecharacteristics,changeinconstituentsofextractableEPSfrommunicipalwastewaterandbeveragewastewatersludgeatvariouspHwasinvestigated.Fouriertransforminfrared(FTIR)spectrophotometrywasusedtoanalyzetheeffectofpHonthefunctionalgroupsinEPS.Surfacechargewasmeasuredbycolloidtitration.Finally,surfacechargemeasurementsandmolecularstructureanalysiswereevidencedbyScanningElectronMicroscopy(SEM)observationofthesludgesamplesbeforeandafterEPSextractionatdifferentpH.Theresultsshowthatatstrongacidcondition(pH3),theextractableEPSarelowerthanthoseatneutralconditionbyabout50%including30%decreasinginpolysaccharidesand65%~70%inprotein.Atstrongalkalicondition(pH11),theextractableEPSarehigherthanthoseatneutralconditionby20%~30%includingabout15%increasinginpolysaccharidesand20%~50%inprotein.Hydroxylchangesbothatalkaliandacidcondition.Carboxylacid,polysaccharides,phenolicgroups,andaminogroupsinproteindisappearatacidcondition(pH3).NegativesurfacechargeofEPSfrombothofthesludgesincreaseswithpH.ObservationofsludgebySEMindicatesthatcomparedwithalkalicondition,acidconditionismoreeffectiveinmakingthebacterialcellbroken.TheresultssuggestthatpHchangestheconstituents,concentrationandfunctionalgroupsinEPS,consequentlythesurfacechargeofEPS.Asaresult,sludgecharacteristicsarechanged.Keywords:extracellularpolymericsubstances(EPS);sludge;pH;molecularstructure;surfacecharge(extracellularpolymericsubstances,EPS),3[1].,EPS()80%,50%~90%,15%,[2~5].EPS.Kang[6],EPS,Houghton[7]EPS;Urbain[1]EPS(SVI),Goodwin[8],Chao[9]EPSSVI.EPS.Morgan[10]EPS,,EPS;Liao[11]28720077ENVIRONMENTALSCIENCEVol.28,No.7Jul.,2007EPS,EPS,.pH,EPS,.[12]pH,[13][14]pH.,pH,.pHEPS,pHEPS,,pH,EPS.11.1.1.1Table1CharacteristicsofthestudiedactivatedsludgeTSSmgL-1VSSmgL-1pH%2536083407.898.630886109007.296.21.21molLHNO3NaOHpH37113,,,.:,80100kPa10min,8000rmin10min,,15,,EPS[15].13131MLSSVSSTPTN[16].132,Folin[17],[18];EPSPerkinElmerSpectrumGX;EPS[10].133:,25%424h,30%50%70%80%90%100%10min.221pHEPSpH,EPS1.1,2EPSpH.(pH3),EPSpH750%,30%,65%;EPSpH750%,30%,70%.(pH11),EPSpH720%,15%,20%;EPSpH730%,15%,47%.1EPSpHFig.1VariationofcompositionandconcentrationofEPSwithpH150828,pHEPS,pH,EPS(),EPS,.,pHEPS.22pHEPSpH2.2,2EPSpH.(pH3),EPS,506799,(pH11),2EPS,pH711,EPS51.EPSpHEPS,EPS2pHEPSFig.2VariationofsurfacechargeofEPSwithpH.H+OH-,.23pHEPSpHEPS(400~4000cm-1)32,2IREPS.3pHEPSFig.3FTIRspectraofEPSatvariouspH2IRTable2MainfunctionalgroupsobservedinIRspectracm-13000~3400OHEPSOH2926!10CH21720CO1630~1680CO∀()1580~1630C#H∃()N#H1400COOH1240COOH1230COOH1030~1150C#O#C950~1120CH1000EPS.;,()(CH2);[19].EPSpH.3099(EPS)3065!20(EPS);1170~1560(EPS)1008~1611()(pH3),.EPS15097:pH,,EPS,EPS,.24pHEPS,pHEPS,4.4(a)EPS[20],4,EPS,,,1.4(b)~(d)EPS,,EPSEPS,,EPS,,.4Fig.4ElectronmicrographofactivatedsludgeatdifferentconditionEPS,,;,EPS,EPS,EPS,,EPS,,.3(1)EPSpH.(pH3),EPSpH750%,30%,65%~70%;(pH11),EPSpH720%~30%,15%,20%~50%.(2)EPSpH,2EPS.,,,,H+OH-.(3),,EPS,;,EPS,.(4)pHEPS,EPS151028,.:[1]UrbainV,BlockJC,ManemJ.Bioflocculationinactivatedsludge,ananalyticalapproach[J].WatSciTech,1993,25:441~443.[2]FrlundB,PalmgrenR,KeidingK,etal.Extractionofextracellularpolymersfromactivatedsludgeusingacationexchangeresin[J].WatRes,1996,30:1749~1758.[3]ElisabethN,JanR,RafD,etal.Advancedsludgetreatmentaffectsextracellularpolymericsubstancestoimproveactivatedsludgedewatering[J].JHazardMat,2004,106B:83~92.[4]MagaraY,NumbuS,UtosawaK.Biochemicalandphysicalpropertiesofanactivatedsludgeonsettlingcharacteristics[J].WatRes,1986,10(1):71~77.[5]SaninFD,VesilindPA.Effectofcentrifugationontheremovalofextracellularpolymersandphysicalpropertiesofactivatedsludge[J].WatSciTech,1994,30(8):117~127.[6]KangSM,KishimotoM,ShioyaS,etal.Dewateringcharacteristicsofactivatedsludgesandeffectofextracellularpolymer[J].JFermentBioeng,1989,68(2):117~122.[7]HoughtonJI,QuarmbyJ,StephensonT.Municipalwastewatersludgedewaterabilityandthepresenceofmicrobialextracellularpolymer[J].WatSciTech,2001,44:373~379.[8]GoodwinJAS,ForsterCF.Afurtherexaminationintothecompositionofactivatedsludgesurfacesinrelationtotheirsettlementcharacteristics[J].WatRes,1985,19:527~533.[9]ChaoAC,KeinathTM.Influenceofprocessloadingintensityonsludgeclaricationandthickeningcharacteristics[J].WatRes,1979,13(12):1213~1220.[10]MorganJW,ForsterCF,EvisonL.Acomparativestudyofthenatureofbiopolymersextractedformanaerobicand